Black Screen of Death issue

One of my friends has a Black Screen of Death issue and basically we have tried running the WGA Cracker several times, but it doesn't seem to work. After running the program the BSD goes away, but then gets back after turning on the pc the next morning.

She also tried to delete the Windows Validation License but that didn't seem to work either.

It's a Windows XP anti-piracy measure; the black screen of death appears if Windows decides it's a pirate copy. The solution is to buy a copy (really, you shouldn't have bought a PC without Windows on it, because as you can see from the Amazon prices the so-called "Microsoft tax" is a lot less than buying a copy of Windows).

Alternatively if you do legally own the software then contact Microsoft for a solution; the problem means that your licence key is circulating and Microsoft have spotted the forgery, so simply present them with your proof of purchase and they'll give you a new licence key. It may not be your fault the key is circulating, maybe you bought the PC off a dodgy dealer or something.